Numerous agents and methods for suppressing and/orextinguishing fires are known and can be selected for a particular fire, depending upon factors such as size, location and the type of combustible materials involved.
Certain halogenated hydrocarbon extinguishants have been used in the fire protection industry, particularly in applications including total flooding applications, where an enclosed area is completely filled (“flooded”) with an effective amount of the agent (e.g., computer rooms, storage vaults, telecommunications switching gear rooms, libraries, document archives, petroleum pipeline pumping stations, and the like), or in streaming applications where the extinguishant is directed towards the location of the fire (e.g., commercial hand-held extinguishers). Such extinguishants are not only effective but, unlike water, also function as “clean extinguishants”, causing little, if any, damage to the enclosure or its contents.
Previously, the most commonly-used halogenated hydrocarbon extinguishants have been bromine-containing compounds such as bromotrifluoromethane (CF3Br, Halon 1301) and bromochlorodifluoromethane (CF2ClBr, Halon 1211). While these bromine-containing halocarbons are highly effective in extinguishing fires and can be dispensed either from streaming equipment or from a total flooding system, these compounds have been linked to the destruction of stratospheric ozone (“ozone depletion”). For example, Halon 1301 has an Ozone Depletion Potential (ODP) of about 10, and Halon 1211 has and ODP of about 3. In 1987, a number of governments signed the Montreal Protocol to protect the global environment, setting forth a timetable for phasing out ozone depleting products, including the bromine-containing halocarbons.
Furthermore, certain of these compounds have issues with toxicity even at relatively low concentration levels. For example, Halon 1211 causes cardiac sensitization when used at levels above 1-2% vol in air.
In response to the requirement for a non-flammable, non-toxic alternative to the bromine-containing halocarbons, the industry developed a number of hydrofluorocarbons (HFCs) which have zero ozone depletion potential. For example, 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) has been adopted in certain fire extinguishing applications and also does not contribute to ozone depletion.
However, HFC-227ea has a Global Warming Potential (GWP) of about 3220 (according to IPCC (2007) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. S. Solomon et al., Cambridge University Press. Cambridge, United Kingdom). There is therefore a need in the art for clean fire extinguishants with both a low Ozone Depletion Potential (ODP) and a low Global Warming Potential (GWP) . . . .
It is understood in the art that replacement clean fire extinguishants must possess a mosaic of properties in order to be capable of effectively and safely extinguishing a fire, preferably with minimum unwanted consequences. That mosaic generally includes excellent fire extinguishing properties, as well as chemical stability, low or no toxicity, amongst others. The replacement clean fire extinguishants must also have acceptable environmental properties, i.e. low Global Warming Potential (GWP) and low Ozone Depletion Potential (ODP). However, the identification of a flame extinguishant meeting all of these requirements is presents a significant challenge to those skilled in the art.
It is also desirable to provide a fire extinguishant which is gaseous at room temperature (i.e. about 21° C.), or which has a boiling point at or about room temperature (i.e. about 21° C.), when measured at about atmospheric pressure (i.e. at about 1 atm). Although fire extinguishants which have a boiling point above room temperature (and are therefore liquid when discharged) can be used, a fire extinguishant which has a boiling point at or about room temperature (i.e. about 21° C.) will evaporate more quickly than a fire extinguishant which has a boiling point above room temperature, and thus fill the area surrounding the flame to be extinguished (or the area to be inerted) faster, all other things being equal.
WO02007/002625 discloses that fluoroalkenes of formula (I), XCFzR3-z, can be used in a method of suppressing a flame. Monochloro, trifluoropropenes (HFO-1233), including 1-chloro-3,3,3-triflouropropene (HFO-1233zd), are disclosed as compounds of formula (I).
U.S. Pat. No. 9,387,352 discloses liquid extinguishing/inerting systems for suppressing fire and identifies 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone as a potential liquid extinguishing agent.
Applicants have come to appreciate that the previously available fire suppression compositions, systems and methods have one or more disadvantages. For example, while 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone has a degree of effectiveness in flame suppression, it is also a liquid at room temperature and as a consequence may tend to be deposited as a liquid on surfaces in the fire suppression areas. Such a situation can be disadvantageous in that the materials that are coated with the liquid will subsequently need to be cleaned, or in some cases may need to be repaired or replaced.